[emms-help] [patch] PulseAudio volume

[Rasmus]

Hi,

I added support for the awesome¹ volume control of PuleAudio.  It would be
great if somebody with more advance PA setup would test it before I push
it.  ATM it increases the *system volume*, but in principal it could be
used to change the volume of whatever EMMS uses for playing.  Let me know
if you think this something that EMMS should do (I don't know how to
actually do this via the terminal).

Thanks,
Rasmus

Footnotes: 
¹ Why is PA awesome?  Because it can set an arbitrary volume, e.g.  200%
  which is great for laptops.

-- 
I hear there's rumors on the, uh, Internets. . .

>From f2a730688256a102c37ef67614eb76b5ed9db436 Mon Sep 17 00:00:00 2001
From: Rasmus <address@hidden>
Date: Fri, 13 Mar 2015 01:05:31 +0100
Subject: [PATCH] emms-volume: Support for pulseaudio.

emms-volume-pulse.el adds support for PulseAudio pactl.
---
 NEWS                      |  2 +
 doc/emms.texinfo          |  4 +-
 lisp/emms-volume-pulse.el | 98 +++++++++++++++++++++++++++++++++++++++++++++++
 lisp/emms-volume.el       |  1 +
 4 files changed, 103 insertions(+), 2 deletions(-)
 create mode 100644 lisp/emms-volume-pulse.el

diff --git a/NEWS b/NEWS
index 6acba63..35becea 100644
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,8 @@ News since version 4.0:
   - Covers can have several extensions.  See
     `emms-browser-covers-file-extensions'.
   - Libre.fm login details can, and should, be stored in authinfo now.
+  - Possible to set volume via PulseAudio pactl via
+    emms-volume-pulse.el.
 
 News since version 3.0:
 
diff --git a/doc/emms.texinfo b/doc/emms.texinfo
index 40bb6f1..26bb10f 100644
--- a/doc/emms.texinfo
+++ b/doc/emms.texinfo
@@ -2425,8 +2425,8 @@ value. So instead of pressing @kbd{C-c +} six times to 
increase volume
 by six steps of @code{emms-volume-change-amount}, you would simply type
 @kbd{C-c + + + + + +}.
 
-
-
+EMMS can change volume with amixer, mpd, PulseAudio out of the box, see
address@hidden
 
 @node Streaming Audio
 @chapter Streaming Audio
diff --git a/lisp/emms-volume-pulse.el b/lisp/emms-volume-pulse.el
new file mode 100644
index 0000000..ca59778
--- /dev/null
+++ b/lisp/emms-volume-pulse.el
@@ -0,0 +1,98 @@
+;;; emms-volume-pulse.el --- a mode for changing volume using PulseAudio pactl
+
+;; Copyright (C) 2015 Free Software Foundation, Inc.
+
+;; Author: Rasmus Pank Roulund <address@hidden>
+
+;; This file is part of EMMS.
+
+;; EMMS is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 3, or (at your option)
+;; any later version.
+;;
+;; EMMS is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+;;
+;; You should have received a copy of the GNU General Public License
+;; along with EMMS; see the file COPYING.  If not, write to the
+;; Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
+
+;;; Commentary:
+
+;; This file defines a few simple functions to raise or lower the volume
+;; using pactl. It can be used stand-alone, though it's meant for usage
+;; with EMMS, particularly with emms-volume.el
+
+;;; History:
+
+;; Marts 2015: First release.  Partly based on emms-volume-amixer.el
+
+;;; Todo:
+
+;; There probably needs to be more configurability, which may in turn
+;; mean adding some more functions.
+;; Some of this could benefit from adding customize interfaces.
+
+;;; Code:
+
+(eval-when-compile (require 'cl))
+
+;; TODO: it would be great if custom could have
+;; choices based on pactl list short sinks | cut -f1-2
+
+(defcustom emms-volume-pulse-sink 0
+  "The sink to use for volume adjustment.
+
+See full list of devices on your system by running
+    pactl list short sinks"
+  :type '(choice (number :tag "Sink number")
+                 (string :tag "Sink symbolic name"))
+  :group 'emms-volume)
+
+(defun emms-volume--pulse-get-volume ()
+  "Return `emms-volume-pulse-sink' volume."
+  (let ((sink-number-p (numberp emms-volume-pulse-sink))
+        (start 0)
+        (output
+         (shell-command-to-string
+          (concat "pactl list sinks" "|"
+                  "grep -E -e 'Sink' -e 'Name' -e  '^[^a-zA-Z]*Volume'"))))
+    (car
+     (reverse
+      (funcall
+       (if sink-number-p 'assq 'assoc)
+       emms-volume-pulse-sink
+       (mapcar (if sink-number-p 'identity 'cdr)
+               (loop while
+                     (string-match
+                      (mapconcat 'identity
+                                 '(".*Sink[ \t]+\\#\\([0-9]\\)"
+                                   ".*Name:[ \t]\\([^\n]+\\)"
+                                   ".*Volume:.*?\\([0-9]+%\\).*\n?")
+                                 "\n")
+                      output)
+                     collect (list (string-to-number (match-string 1 output))
+                                   (match-string 2 output)
+                                   (match-string 3 output))
+                     do (setq output (replace-match "" nil nil output)))))))))
+
+;;;###autoload
+(defun emms-volume-pulse-change (amount)
+  "Change amixer master volume by AMOUNT."
+  (message "Volume is: %s"
+           (let ((pactl (or (executable-find "pactl")
+                            (error "pactl is not in PATH"))))
+             (when (zerop (shell-command
+                           (format "%s set-sink-volume %s %s%s%%"
+                                   pactl emms-volume-pulse-sink
+                                   (if (> amount 0) "+" "-")
+                                   amount)))
+               (emms-volume--pulse-get-volume)))))
+
+(provide 'emms-volume-pulse)
+
+;;; emms-volume-pulse.el ends here
diff --git a/lisp/emms-volume.el b/lisp/emms-volume.el
index 846cd30..cca8d77 100644
--- a/lisp/emms-volume.el
+++ b/lisp/emms-volume.el
@@ -61,6 +61,7 @@
 If you have your own functions for changing volume, set this."
   :type '(choice (const :tag "Amixer" emms-volume-amixer-change)
                  (const :tag "MPD" emms-volume-mpd-change)
+                 (const :tag "Pulseaudio" emms-volume-pule-change)
                  (function :tag "Lisp function"))
   :group 'emms-volume)
 
-- 
2.3.2